Documents scanned using an Automatic Document Feeder (“ADF”) may be mis-registered or skewed, which result in a skewed image. A document may be skewed by a shift in in-track and/or cross-track directions, or by an angular rotation. To correct the skewed image, some mechanical techniques have been proposed. However, these mechanical methods tend to be unreliable. This problem may be partially solved by using de-skew software algorithms that have been proposed to correct only angular rotations errors. These methods, however, may cause reduced productivity, because the whole image of the document has to be captured, stored in memory, and then retrieved for correction. These prior methods operate on post-rendered binary images that may result in poor image quality, because they do not use the full bit-depth image captured by the scanner.
There is, therefore, a need for a method and system for real-time skew correction that operates during scan operation and prior to rendering the entire image, which does not reduce productivity and image quality.